Alkylthio-, (acetylthio)-and (arylthio)-undecanoic acids



United. States Patent (ALKYLTHIO)-, (ACETYLTHIO)- AND (ARYLTHKD- UNDECANOIC ACIDS Nathan H. Koenig, Elkins Park, and Daniel Swern, Philadelphia, Pa., assignors to the United States of America as represented by the Secretary of Agriculture No Drawing. Application May 28, 1957 Serial No. 662,299

1 Claim. (Cl. 260-400) (Granted under Title 35, US. Code (1952), see. 266) A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government with power to grant sublicenses for such purposes, is hereby granted" to the Government of the United States of America.

The present application is a continuation-in-part of the copending application by Nathan H. Koenig and Daniel Swern entitled LongChainSulfides, Serial No. 637,334,

filed January 30, 1957.

This invention relates to sulfur containing derivatives of IO-undecenoic acid, particularly the organic sulfides formed by the addition of thiols to 10-undecenoic acid. The compounds of the present invention may be represented by the general formula RS (CH COOH cmesn cri=cnkont e 9 or'rorripmonimo on (Equation) 2 Thesulfur compound which is being added, thiolacetic acid, is a thiolacid'ratherthan a simple thiol, and the product is a thiolester rather than a simple sulfide. This product may be called 11-(acetylthio)-undecanoic acid or l0-carboxydecyl thiolacetate depending on Whether one choses to name the molecule as a substituted undecanoic acid or as an ester of thiolacetic acid.

The presence of the carbonyl (CO) group adjacent to the sulfur atom confers special chemical properties on the molecule; consequently Equation 2 is a special case of the general reaction described by Equation 1.

In the aforementioned copending application, we discussed utilization of organic sulfides and illustrated the use of derivatives of (carboxymethylthio)-undecanoic acid as low-temperature plasticizers. In addition to their possible use in the preparation of greases, lubricant additives, emulsifiers, soaps and other surface-active agents, the new compounds of the present invention serve as chemical intermediates for the preparation of sulfoxides, sulfones, amides, amines, esters, and other classes of use ful organic compounds.

One of the reactions of 1l-(acetylthio)-undecanoic acid, which illustrates how it differs from the (alkylthio)- and (arylthio)-undecanoic acids, is the reaction with peracetic acid (Example 13). Instead of the unexpected 1l-(acetylsulfonyl)-undecanoic acid, the isolated product is ll-sulfoundecanoic acid,

(HO S(CH COOH) This molecule has two polar acid groups separated by a long linear hydrocarbon chain. This structure makes this compound useful as a base for surface-active materials, such as water-soluble soaps, and as an intermediate for linear polymers.

The 10-undecenoic acid (B.P. 136 at. 1.5 mm., n =1.4458) used in the reactions had been purified by fractional distillation of the best commercial material. Most of the thiols were the best commercial grades. n-Octanethiol (B.P. 77 at 33 mm.) was also fractionated prior to use. Mercaptoethanol, thiolacetic acid and benzenethiol were practical grade reagents. The preparation and properties of certain (alkylthio)- and (arylthio)- undecanoic acids, 1l-(acetylthio)-undecanoic acid, and ll-sulfoundecanoic acid, will now be described in greater detail.

EXAMPLE 1 11 (n-heptylthio) undecanoic acid.-10 undecenoic acid (45.6 g., 0.25 mole) and n-heptanethiol (33.3 g., 0.25 mole) were mixed in a quartz flask and irradiated at a distance of 1 inch by a 140 watt ultraviolet lamp (high pressure. quartz mercury arc). After three hours of irradiation, during which time the temperature rose to about 80, the reaction product was crystallized three times at 4 from 600-rnl. portions of petroleum ether, yielding 49 g. (62% yield) of 11-(n-heptylthio)-undecanoic acid, M.P. 53-54".

EXAMPLE 2 ll-(acetylihio)-undecan0ic acid.-10 undeceneoic acid (11.1 g., 0.060 mole) and thiolacetic acid (4.7 g., 0.062 mole) were irradiated at 2 inches from a watt ultraviolet lamp for 1 hour (temperature, 70). The solid reaction product, after extraction with petroleum ether, left nearly pure l1-(acetylthio)-undecanoic acid, M.P. 56-58, in 55% yield.

'The other compounds listed in Table I as Examples 3 to 12 were prepared in a similar fashion with the following exceptions.

. EXAMPLE 9 p 1 I-(Z-hydroxyethyifhio)-zmdeczmoic acid. -Equimolar amounts of mercaptoethanol and 10-undecenoic acid were added we flask and stirred for 1 /2 hours at 60'.. No ultraviolet irradiation was necessary. .The product was recrystallized from acetone-petroleum ether, then acetonitrile, and finally carbon tetrachloride to obtain the analytical sample of 1l-(2-hydroxyethylthio)-undecanoic acid, M.P. 70.

EXAMPLE 11 11- (phenylthio) -undecan0ic acid.-Roughly equimolar amounts of benzenethiol and IO-undecenoic acid, together with a catalytic amount (1%) of lauroyl peroxide, were heated overnight at 60 under an atmosphere of nitrogen. The resulting solid, after removal of petroleum ether solubles, left 1l-(phenylthio)-undecanoic acid, M.P. 83, in 61% yield. Recrystallization from heptane gave the anayltical sample, M.P. 84.

Analytical data for the recrystallized products are summarized in Table I. Melting points were obtained with a micro hot stage apparatus.

EXAMPLE 13 11 -sulfoundecan0ic acid. 11-(acetylthio)-undecanoic acid (5.2 g., 0.02 mole) was dissolved in 20 ml. of acetic acid. Peracetic acid (9 ml. of 40% solution in acetic acid, 0.05 mole) was added dropwise over a 15-minute period so that the temperature reached a maximum of 80. The reaction mixture was evaporated in a desiccator over sodium hydroxide at 25 and 15 mm.

crude product, M.P. 59 62", neut. equiv. 141, corresponded to ll-sulfoundecanoic acid hemihydrate, neut. equiv. 138. An ether-insoluble fraction was separated When the reaction is to proceed over a considerable period of time as in Example 11, where 1% lauroyl peroxide was employed as a catalyst and the mixture was heated overnight at 60, it was considered preferand discarded; the ether-soluble acid was purified by 5 able to displace the air atmosphere with nitrogen, as recrystallization from ether-benzene. Vacuum desiccaoxygen may promote slow side reactions. tion at room temperature gave anhydrous ll-sulfoundec- The molar ratio of thiol to fatty acid is not a critical anoic acid, M.P. ca. 94. factor in the reaction. Starting with equimolar amounts Although infrared and X-ray diffraction studies indicate of the reactants, yields of about 60% were obtained that the addition products have a linear structure, that under the reaction conditions described in Example 1'. is, the sulfur atom is attached at the 11 (terminal) Within limitations, it is considered that the yields would rather than the 10 position of the undecanoic acid, trace vary directly with the ratio of thiol to fatty acid. amounts of the 10 isomer may also be formed. Hence, The reaction temperature is not critical, but for case we do not wish to restrict this invention to ll-substituted of controlling the exothermic reaction we prefer to undecanoic acid. 15 maintain a temperature of about -80".

TABLE 1 11-(alkylthi0)-, (ace tylthio} and (arylthi0)-undecanoic acids RS(CH1)1000:H

Neut. equiv. Carbon, Hydrogen, Sulfur, Example Percent Percent Percent Number R Formula M g.

' Calcd. Found Oaled. Found Calcd. Found Calcd. Found 0111114018 59 260 264 60.0 59.8 9.29 9 27 12.3 12.6 CuHzaOzS 44 260 259 ommnois 274 275 65.6 65.3 11.0 10.9 11.7 11.9 Cl'IHBAOZS 53 303 302 67.5 67.5 11.3 11.4 10.6 10.8 01515145048 54 317 317 68.3 68.5 11.5 11.5 10.1 10.2 0181138018 331 932 69.0 69.0 11.6 11.8 9.70 9.30 n-UndecyL- 0411144018 68 373 372 n-DodecyL- 0251146028 68 387 388 71.4 71.5 12.0 11.8 8.29 8.09 2-Hydroxyethyl... 0111141018 70 262 266 59.5 59.0 10.0 10.3 12.2 12.0 Benz CBHEBOZS 54 308 808 70.1 69.9 9.15 9.14 10.4 10.4 Phenyl. CnHzsOzS 84 294 294 69.3 69.5 8.90 9.26 10.9 11.2 2-Naphthyl 0211128023 99 345 344 73.2 73.1 8.19 8.12 9.31 9.24

9 Determined with a micro hot stage.

The reactions proceed moderately rapidly at temperatures below 100 under free-radical conditions, often with the assistance of ultraviolet light. As is common in free-radical reactions, the rate of reaction of thiols (mercaptans) with the double bond of fatty acids is influenced by physical factors and chemical agents which act as I We claim:

A process for making ll-sulfoundecanoic acid comprising oxidizing 11-(acetylthio)-undecanoic acid with peracetic acid.

References Cited in the file of this patent UNITED STATES PATENTS 2,216,751 Rosen Oct. 8, 1940 2,354,550 Rosen July 25, 1944 2,454,108 Walling Nov. 16, 1948 2,522,476 Wasson Sept. 12, 1950 FOREIGN PATENTS 905,976 France Dec. 19, 1945 

